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When a contrail occurs in a pure and over-saturated air in high altitude, it's also because of the engines emit condensation nuclei.

But if the contrail expands in a wider cirrus, where do the contrails gets the condensation nuclei from? (I'm guessing it's necessary for the expansion of the condensation).

Or can the cloud grow without additional nuclei ?

DeltaLima
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vmonteco
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1 Answers1

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Supersaturated environments just need the initial condensation in order to start the entire condensation process. It doesn't need to find more condensation nuclei particles. The condensation nuclei generated by the engines is enough to start the chain reaction for a cloud to form in the supersaturated environment.

Take this video as an example. It is an aqueous solution but the situation is the same: a single crystal causes the rest of the solids to precipitate out of the solution.

SMS von der Tann
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